Investments (Tables)

9 Months Ended

Sep. 30, 2013

Investments, Debt and Equity Securities [Abstract]

Schedule of Investments

At September 30, 2013 investments classified as available-for-sale securities were as follows:

	Cost		Gross Unrealized Gains		Gross Unrealized Losses		Fair Value
Debt Securities:
U.S. treasury securities	$	124,919	$	54	$	—	$	124,973
Corporate debt securities	22,809		—		1,731		21,078
	$	147,728	$	54	$	1,731	$	146,051

Contractual Maturities of Investments

At September 30, 2013, the contractual maturities of investments classified as available-for-sale were as follows:

	Cost		Fair Value
Due in one year or less	$	124,919	$	124,973
Due after one year through five years	9,090		7,883
Due after five years through ten years	13,719		13,195
	$	147,728	$	146,051